Using vibration to distribute coffee grounds: A new competition trend?

Competitions such as the World Barista Championship have long been a platform to showcase the latest innovations and trends in specialty coffee. In recent years, a growing number of competitors have included advanced distribution tools and techniques in their routines to optimise espresso extraction.

At the 2024 WBC, a new distribution trend may have emerged. Both German Barista Champion Felix Hohlmann and South Korean Champion Junghwan Lim used a newly developed tool that vibrates ground coffee while it’s distributed. During their routines, Hohlmann and Lim highlighted how this helps improve the vertical distribution of grounds, potentially increasing flavour clarity and sweetness.

So, could using vibration to distribute coffee grounds become a new competition trend? And could high-end coffee shops also start to implement these devices behind the bar?

I spoke with Angus Mackie, Head of Customer Support and Innovation Development at Nucleus Coffee Tools, and Dr. Robert McKeon Aloe, independent coffee scientist, for their insight.

You may also like our article on specialty coffee‘s obsession with distribution techniques.

Specialty coffee’s quest for new distribution techniques

Espresso distribution is a way of levelling out ground coffee after grinding and dosing into portafilters. There are several well-known and widely used distribution techniques, some of which make use of specific tools:

• Side tap and settle – tap the portafilter repeatedly with your hand to break up any clumps and then gently tap on an even surface or your hand to flatten the grounds
• NSEW – place your finger across the top of the basket and push the grounds away from your body before pushing them back towards you
• Stockfleth method – similar to the NSEW method, but you also need to rotate the portafilter and your hand in opposite directions
• Shake and dosing cup – grind coffee into a dosing cup, shake, and then pour into the portafilter basket
• Weiss Distribution Technique (WDT) – using a WDT tool (which usually includes fine needles) to stir ground coffee to break up clumps

Dr. Robert McKeon Aloe is an independent coffee scientist and the author of Engineering Better Espresso and Advanced Espresso. He explains why distribution after grinding is so important for espresso.

“Throughout the grinding process, particle size changes from the beginning to the middle to the end,” he says. “This could cause an uneven particle size distribution in the portafilter basket, which could result in channelling or uneven extraction.”

Best practices for espresso distribution

Angus Mackie is the Head of R&D and Customer Support at professional coffee equipment manufacturer Nucleus Coffee Tools. He says among many factors, distribution is an important part of making excellent espresso.

“Every time we grind coffee, there are imperfections in distribution, simply because of the grinding process and the way that the grounds enter the basket,” he explains. “Without optimal distribution, not only do we reduce the ability to access the full potential of the coffee, but we also increase the waste produced from channelling and inconsistent shots.”

Many baristas and competitors opt for WDT tools to achieve as consistent results as possible. These devices break up clumps and evenly distribute coffee grounds. Combined with the shake and dosing cup method (which also reduces static), these techniques can help improve extraction and flavour clarity.

In response to specialty coffee’s growing focus on distribution, a number of equipment manufacturers are developing more advanced tools, including the Nucleus NCD, Barista Hustle’s AutoComb, and the Moonraker from Weber Workshops.

Using vibration to distribute coffee grounds

Distribution tools have been a big part of the World Barista Championship in recent years. At the 2022 edition, Australian competitor Anthony Douglas used the Autocomb, a manual espresso distribution tool never seen before on the global stage. The device consists of a mount, 12 thin needles, and a handle that you spin to move the needles around.

At the 2024 World Barista Championship, five of the seven finalists used the Autocomb in their routines. The German and South Korean competitors Felix Hohlmann and Junghwan Lim, meanwhile, used the NCD Pulse, which combines the NCD distributor tool with pulse vibration technology.

“While spinning the tool on top of the portafilter basket, the NCD Pulse also vibrates, which distributes ground coffee throughout the basket,” Angus tells me. “The practice of making concrete inspired the idea whereby vibration removes air pockets from the lower layers.”

Vibration in the coffee industry, including at competitions, isn’t an entirely new concept, however. Ultrasonic vibration is sometimes used to mix ingredients in signature drinks, and ultrasonic homogenisers can be used to infuse drinks, blend emulsions, and age wine or spirits. 

One of the biggest challenges with using vibration tools for distribution, specifically, is ensuring that coffee is distributed evenly. Robert says that his research has been inconclusive in answering the question of which types of vibration and distribution offer the best results. 

“One of the challenges with these tools is ensuring vibration is even,” he adds. “Sometimes the level of vibration causes the coffee grounds to build up on one side of the portafilter basket.

“Moreover, it’s unknown if vibration homogenises particle distribution throughout the puck,” he adds. “In some tests, it seems that vibration initially moves the particles but only for a few seconds before the coffee grounds settle.”

Benefits of using vibration

Although more research is needed, there are some benefits to using vibration tools during puck preparation.

“Common distribution techniques that baristas use involve tapping the portafilter basket with their hands, but coffee is sensitive. Tapping sideways in one spot with your hand or up and down on the benchtop doesn’t evenly distribute grounds throughout the basket,” Angus says. “Vibration, on the other hand, allows a consistent reshuffling of coffee grounds and air pocket removal, which can be applied fast and precisely.”

Will vibration become a more popular technique at the WBC?

Distribution tools have become the norm in competitors’ routines at the WBC. Given this, vibration is likely to be another element that more will use to their advantage.

“The NCD Pulse made a very successful debut this year in Busan,” Angus says. “Many points go towards the ‘tactile’ and ‘taste experience’ in the espresso beverage round, and tools like the Pulse help enhance mouthfeel, texture, and aftertaste.”

In addition to vibration, competitors could also leverage several other advanced technologies to optimise extraction and enhance desirable flavour attributes. The 2024 Australian Barista Champion Jack Simpson used post-extraction improvement – a technique that uses electromagnetic wave technology – to reduce bitterness and highlight sweetness.

“Following Jack’s routine, I used an ultrasonic mixer post-extraction, and I was so impressed that it’s now part of my usual espresso routine,” Robert says. “Christopher Hendon also put out some research about how passing electric voltages through extracted espresso can change its flavour. 

“Other people have used sound waves to improve extraction,” he adds. “I think these techniques, combined with using more developed roast profiles, could become more popular in competitions, mainly because they reduce bitterness and balance acidity.”

Will this interest extend beyond competitions?

Many coffee shops already use one or several kinds of distribution tools, including WDT and dosing cups. In turn, more advanced tools and techniques which seem to have proven results and could easily be adopted in a café setting.

“Tools which reduce problems and make workflow easier are valuable,” Angus says. “Espresso is a textural beverage – and there is something magical when you find that harmony of taste, flavour, and texture. 

“I can see precise vibration tools becoming adopted beyond high-end coffee shops, making it easier for more people to extract excellent espresso,” he concludes.

The pursuit of extracting the “perfect” espresso has led to the development of many advanced distribution tools. Following the 2024 WBC, it seems using vibration to distribute coffee grounds could become more popular.

Only time will tell if more competitors use these new tools in the future. If the trend picks up, we may see more high-end coffee shops utilising them, too.

Enjoyed this? Then read our article on why distribution and tamping are so important for excellent espresso.

Photo credits: @echo_lou, Nucleus Coffee Tools, Specialty Coffee Association

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